If I have 5 different types of trees and want to plant them in groups of three, how many different combinations of groups can I make.

I worked this out and came out with 30.
Am I right?

Thanks for your help

You are using the word "combinations" so it would be

C(5,3) or 10 of them

e.g.
suppose you have A, B, C, D, E kind of trees
ABC
ABD
ABE
BCD
BCE
CDE
ADE
ACE
BDE
ACD